sciOps: La Silla Science Operations

La Silla - Science Operation Department

EMMI quick reduction tool for spectroscopy

Introduction

The script runs under MIDAS environment and makes use of the MIDAS context long.
If you are not familiar with MIDAS, please refer to this nice MIDAS guide for beginners.
Once started, the script will start from the raw file and produce a bias-subtracted, flat-fielded, wavelength calibrated spectra
and it will ask if you want to measure the S/N ratio.
This last part is done in an interactive way in user's selected area of the spectra.
Please feel free to use the script at home if you wish, but be aware of the fact that this script is intended for quick look purpose ONLY;
it is NOT adequate in its current verison for full reduction of science frames.
Please report any bug to the mail address below; any comment or suggestion for improvement is welcome!

What the script needs

The input files are the raw, 2D spectra, the name of the output frame, the EMMI mode (BLUE/RED) and eventually the name of the master flat and that of the wavelength calibration session.

Master flats and arcs with binning 2 for RILD are available for all the grisms in /data/NTTOPS/pipeline_database/EMMI/master_flats and in /data/NTTOPS/pipeline_database/EMMI/master_arcs. Adequate calibrations will be automatically copied from there in the directory where you are working (usually /data/raw/YYYY-MM_DD on the NTT offline machine) once you launch the script
For BLMD and REMD spectroscopy or RILD in binning 1 you will have to built you own master flat in the afternoon, using the script emmi_fcomb.prg, also available on the offline machine.
A wavelength calibration will also be necessary for REMD, BLMD and RILD in binning 1 mode; this one can be obtained with the MIDAS context long

The extraction of the spectra can be done in two ways:

an interactive or extragalactic mode, especially useful for extended sources, where you will be asked to interactively select with the mouse the object (lower and upper part); and two regions of the sky, below and above the object (always click on the lower side first)
a "stellar" extraction mode, where, once you have selected the sky region, the object spectrum will be extracted on a 3 x FWHM region and plotted in graphic window.
This mode is especially useful when you have short exposures and wish to continually monitor the behaviour of the spectra and/or for stellar targets.

Should you wish to do so, once you have the reduced 1D spectra, you can estimate the S/N in the wavelength range of your choice: for this just set the last parameter to 1 (see below)

How do I make it working?

The script concept is based on the usual MIDAS scripting convention, which means issuing the command, followed by some parameters.
On the offline workstation go to the /data/raw/YYYY-MM-DD directory, type inmidas, then, from a MIDAS prompt, type:

@@ emmi_quickred inputframe outputframe mode [masterflat] [masterarc] [extragalactic?] [snr]

where:
inputframe = name of the input frame (with fits extension)
outputframe = name of the output frame (no bdf extension)
mode = which EMMI mode you are using. Can be BLUE or RED
[masterflat] = name of the masterflat frame (no extension). There is no need for it if you are working in RILD, bin=2 (place a ? instead)
[masterarc] = name of the master wavelength calibration (no extension). Again no need for it if you are working in RILD, bin=2 (place a ? instead)
[extragalactic] = 1 for interactive extraction, 0 for automatic extraction. Defaulted to 0
[snr] = 1 for estimate of S/N ratio of the spectra, 0 for no estimate. Defaulted to 0

That's it!

La Silla - Science Operation Department EMMI quick reduction tool for spectroscopy

Introduction

What the script needs

How do I make it working?

La Silla - Science Operation Department

EMMI quick reduction tool for spectroscopy